In construction work, such as in the building of bridges, it is necessary to provide workers with safety apparatus to protect them in the event of a fall. One such safety apparatus involves the use of a horizontal lifeline which extends between two spaced apart fixedly mounted anchors. It is customary to have the worker attach a pulley to the lifeline and to attach a fall arrestor such as that described in U.S. Pat. No. 4,589,523 which is incorporated herein by reference thereto, to the pulley and to a harness worn by the worker. A turnbuckle is used to adjust the tension in the lifeline. The amount of sag in the lifeline is critical since the pulley must be moved over the cable as the worker moves. Also, the tension in the lifeline is critical since this determines the angle of sag in a lifeline which in turn determines the load amplification by which a vertical fall arrest force applied to the lifeline is multiplied by. Therefore, it is important to know the amount of tension applied to a lifeline. It is also desirable to have a shock absorber to absorb the initial force placed on the anchor of the lifeline and to be able to have controlled elongation of the lifeline under load to increase the sag angle and therefore reduce the amplification.
In some prior art practices, the lifeline is made from an elastomeric material for absorbing the shock of a fallen worker. In this type of installation, it is difficult to control the vertical fall distance because the horizontal lifeline stretches as a function of its initial length.
It is a common practice to support electric power cables on spaced apart supports so that they hang like a horizontal lifeline using insulators to connect the electric power cable to the support. If an insulator of the electric power cable is broken at one of the supports, the electric power cable falls and the resulting forces.